Safety feed device



Feb. 29, 1944. E. B. RILEY f 2,342,694

SAFETY FEED DEVICE Filed July s, 1942 Ellwmrth E Rlay JLJ Patented Feb. 29, 1944 SAFETY FEED DEVICE Ellsworth B. Riley, Philadelphia, Pa.

Application July 8, 1942, Serial No. ll50,179

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. '157) 2 Claims.

The invention described herein may be manufactured and used by o-r for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a safety feed device for a press and is particularly applicable to a punch press in which a series of operations are performed on a strip of material after which the strip is cut into a series of small units.

Many articles such as the circular plates of a mechanical time fuse are made from a strip of material in a progressive die. In this type of ma.- chine the material is fed in at one end and a series of different punching and shaving operations are performed on the strip, the last step being to cut the strip into units, forming the round plates. The dies in such a press are very expensive, so that it is important to avoid injuring them. If the strip is not moved approximate- 1y the proper distance forward in each step the dies may be 4brought down on solid metal. Since some of the dies are designed only for shaving, the contact of such a die with the solid strip results in injury.

One of the first operations performed on the strip is the punching of a hole which is used as a centering hole in the subsequent operations. However, this will take care of only minor variations in feed and will not correct the gross errors which result in damage.

It is therefore the object of the present invention to provide a safety Ifeed for presses which will make it substantially impossible to harm a die because of a mis-feed, Other objects will be apparent on reading the specification.

In general, the above object is achieved by providing an arm or detent which contacts the work and which prevents the operation of the press unless the work is correctly centered.

In the drawing, Figure 1 represents, in plan, the base, feed way and a work piece of a multiple acting press with the present invention in place. T'he dies which reciprocate over the feed way have been removed. Figure 2 represents the controls of a hand fed press showing one manner of utilizing the present invention in conjunction with such a control.

Referring to the drawing by reference characters, the bed l of a press is provided with a feed Way 2 for receiving a work piece. A strip of metal 3 is fed into the feed way where it is acted upon by a series of dies. A stop t at one end of the bed and shoulders 5 on the feed way prevent the strip from being thrust too far between strokes of the die. However, there isf nothing which insures that the strip is fed completely up to the proper position, or to prevent its slipping back when it does get to the proper place. To remedy this situation a sliding arm or detent 5 is provided which slides in a slot cut in the feed way. Arm 6 is forced into Contact with the work piece by means of a spring 'l acting against a stop 8 which is fastened to the bed of the press. Arm E is set at such an angle that it yields when material is pushed into the feedway, ybut will not allow the material to be withdrawn. The outer end of arm 6 is provided with a projection 9 which comes in Contact with and closes a switch i0 when the arm is fully drawn into the feed slot. Switch I0 is of the normally open type. When the arm is partially or fully Withdrawn from the slot switch I0 is opened.

In Figure 2 there is shown the treadle operated control of the die. When foot pedal Il is depressed, valve !2 is opened allowing compressed air to enter cylinder l 3 from a source not shown. This causes control rod I4 to move downward, engaging the clutch (not shown) which operates the die. A small arm l5 is provided on rod It and directly under arm l5 a pivoted catch I6 of ferromagnetic material is placed. This catch is normally held in engagement with arm i5 by means of a spring Il. An electromagnet I8 is suspended in proximity to catch I6 so that when the electromagnet is energized catch I6 is drawn out of contact from arm l5. Thus, when the electromagnet is energized rod I4 is free to move and to operate the clutch bringing down the dies but if the electromagnet is not energized the clutch is locked so that the operator cannot bring down the dies. In operation, a suitable source of current is provided to energize the electromagnet and switch l0 is connected so that it closes the circuit.

This invention has been described in connection with a pneumatically actuated manual press, but it is apparent that the exact method of connecting the control illustrated need not be used. Similarly, the invention is not limited to devices on which only punching and shaving operations are performed but is applicable to other devices as Well, such as multiple acting drawn presses.

I claim:

1. In combination with a punch-press, a longitudinal guideway for a strip of stock to be operated upon, a stop to limit the forward longitudinal movement of the stock through said guideway, a slidable detent spring-urged obliquely into said guideway into the path of movement of the work in entering it in said guideway wherein it is adapted to engage a sheared portion ofthe stock to prevent retrogressive movement of said stock, and electromagnetic means operated by said oletent only when the detent is in engagement with the stock to allow further press operations.

2. In combination with a punch press, stock to be progressively operated upon by the punch press, a stopv to limit the forward-longitudinal motion of the stock, a sliding detent to tangentially engage a sheared portion of the stock to prevent retrogressive movement and an electromagnetic unlocking det-ent actuated by the sliding detent to permit press operation onIy on full engagement of the sliding detent with a sheared portion of the stock.

ELLSWORTH B. RILEY. 

